Positioning structure of a single-pull reel

A single-pull reel comprising:

• an upper cover having a center provided with a downwardly extending axle, said axle having a lower end provided with a notch;
• a bottom cover configured to engage with said upper cover;
• a cord-rotating disc having a top portion, a bottom portion and a center hole, said top portion being provided with a circular flange which is divided into a plurality of sections by a plurality of slots, a clamping member being provided on said top section of said cord-rotating disc to form a passage between said clamping member and one of said sections and having engaging means at an inner side against said one of said sections, said bottom portion being provided with a sliding groove;
• a spiral spring having an inner end and an outer end, said inner end being engaged with said notch of said axle of said upper cover, said outer end being bent into a hook to engage with one of said sections of said cord-rotating disc;
• a cord divided into a first section and a second section by an enlarged block, said block having an engaging means engaged with said engaging means of said clamping member, said first section of said cord being wound around said first flange of said cord-rotating disc, said second section of said cord extending out of a hole from said top portion of said cord-rotating disc to said bottom portion of said cord-rotating disc;
• a positioning ball mounted within said sliding groove of said cord-rotating disc thereby forming an engaged sliding movement;
• and
• said bottom cover having an inner face provided with a multi-functional rail in combination with said positioning ball to provide a clockwise and counterclockwise movement of said cord-rotating disc thereby causing said positioning ball to provide alternately a loosening and tightening operation of said cord.